We need a expert with our Linux server which we can access via WHM and SSH.
Clients are having issues sending between domains hosted on that same server - eg. we have a domain that has it's mail hosted on that server and which has a dedicated IP address, and another domain that has a different dedicated IP address but who's mail is set to remote manage as they have their own internal Windows Exchange server to handle their mail. The clients from the windows exchange domain cannot email the other client's domain as it bounces back.
Also, there are issues sending emails as some are bouncing back - the ip address of the server is blocked for anti-spam by some, so we need to work out why it is getting blocked and clear these.
Also, a check on the overal setup of the DNS of the sites hosted on this server, the email setup and the security would be good.
I have not had good experience in the past with people looking into these issues, so we'd be after someone with great skills and experience that specialises in this.
All of this needs to be done ASAP so we'd be after someone who is available immediately.